Abstract:

A deep drawing packaging container comprising: a top film made of a first
heat shrinkable multilayer film; and a bottom film made of a second heat
shrinkable multilayer film, the deep drawing packaging container being
formed by deep drawing, so that a drawing ratio (D1) of the top film
and a drawing ratio (D2) of the bottom film satisfy conditions:
D1=1.1 to 4.0;
D2=1.5 to 5.0; and
(D2/D1)=1.05 to 4.55,
wherein a hot-water shrinkability (SM1) in a longitudinal direction
and a hot-water shrinkability (ST1) in a transverse direction of the
first heat shrinkable multilayer film and a hot-water shrinkability
(SM2) in a longitudinal direction and a hot-water shrinkability
(ST2) in a transverse direction of the second heat shrinkable
multilayer film satisfy conditions:
SM1=5 to 40%;
ST1=5 to 40%;
SM2=2 to 25%;
ST2=2 to 25%;
(SM1/SM2)=1.2 to 12; and
(ST1/ST2)=1.2 to 12
(where the hot-water shrinkability is a shrinkability (%) after immersing
the heat shrinkable multilayer film before drawing in hot water of
90° C. for 10 seconds).

Claims:

1. A deep drawing packaging container comprising: a top film made of a
first heat shrinkable multilayer film; and a bottom film made of a second
heat shrinkable multilayer film, the deep drawing packaging container
being formed by deep drawing, so that a drawing ratio (D1) of the
top film and a drawing ratio (D2) of the bottom film satisfy the
following conditions:D1=1.1 to 4.0;D2=1.5 to 5.0;
and(D2/D1)=1.05 to 4.55,wherein a hot-water shrinkability
(SM1) in a longitudinal direction and a hot-water shrinkability
(ST1) in a transverse direction of the first heat shrinkable
multilayer film and a hot-water shrinkability (SM2) in a
longitudinal direction and a hot-water shrinkability (ST2) in a
transverse direction of the second heat shrinkable multilayer film
satisfy the following conditions:SM1=5 to 40%;ST1=5 to
40%;SM2=2 to 25%;ST2=2 to 25%;(SM1/SM2)=1.2 to 12;
and(ST1/ST2)=1.2 to 12,(where the hot-water shrinkability is a
shrinkability (%) after immersing the heat shrinkable multilayer film
before drawing in hot water of a temperature of 90.degree. C. for 10
seconds).

2. The deep drawing package container according to claim 1, wherein each
of the first heat shrinkable multilayer film and the second heat
shrinkable multilayer film comprises at least an outer layer made of a
first thermoplastic resin, an intermediate layer made of a
polyamide-based resin and an inner layer made of a sealant resin.

3. The deep drawing package container according to claim 1, wherein a
total thickness (T1) of the first heat shrinkable multilayer film
before drawing and a total thickness (T2) of the second heat
shrinkable multilayer film before drawing satisfy the following
conditions:T1=20 to 120 μm;T2=45 to 200 μm;
and(T2/T1)=1.1 to 10.

4. A deep drawing packaged product comprising:a packaging container
obtained by sealing and further heat-shrinking the top film and the
bottom film of the deep drawing packaging container according to claim 1;
andcontents placed inside the packaging container.

5. A method for manufacturing a deep drawing packaging container
comprising a top film made of a first heat shrinkable multilayer film and
a bottom film made of a second heat shrinkable multilayer film, the
method comprising the steps of:preparing the first heat shrinkable
multilayer film and the second heat shrinkable multilayer film in which a
hot-water shrinkability (SM1) in a longitudinal direction and a
hot-water shrinkability (ST1) in a transverse direction of the first
heat shrinkable multilayer film and a hot-water shrinkability (SM2)
in a longitudinal direction and a hot-water shrinkability (ST2) in a
transverse direction of the second heat shrinkable multilayer film
satisfy the following conditions:SM1=5 to 40%;ST1=5 to
40%;SM2=2 to 25%;ST2=2 to 25%;(SM1/SM2)=1.2 to 12;
and(ST1/ST2)=1.2 to 12,(where the hot-water shrinkability is a
shrinkability (%) after immersing the heat shrinkable multilayer film
before drawing in hot water of a temperature of 90.degree. C. for 10
seconds); andperforming deep drawing so that a drawing ratio (D1) of
the top film and a drawing ratio (D2) of the bottom film satisfy the
following conditions:D1=1.1 to 4.0;D2=1.5 to 5.0;
and(D2/D1)=1.05 to 4.55.

6. The method for manufacturing a deep drawing packaging container
according to claim 5, wherein each of the first heat shrinkable
multilayer film and the second heat shrinkable multilayer film comprises
at least an outer layer made of a first thermoplastic resin, an
intermediate layer made of a polyamide-based resin and an inner layer
made of a sealant resin.

7. The method for manufacturing a deep drawing packaging container
according to claim 5, wherein a total thickness (T1) of the first
heat shrinkable multilayer film before drawing and a total thickness
(T2) of the second heat shrinkable multilayer film before drawing
satisfy the following conditions:T1=20 to 120 μm;T2=45 to
200 μm; and(T2/T1)=1.1 to 10.

8. A method for manufacturing a deep drawing packaged product comprising
the steps of:placing contents in a space between the top film and the
bottom film of the deep drawing packaging container comprising: a top
film made of a first heat shrinkable multilayer film; and a bottom film
made of a second heat shrinkable multilayer film, the deep drawing
packaging container being formed by deep drawing, so that a drawing ratio
(D1) of the top film and a drawing ratio (D2) of the bottom
film satisfy the following conditions:D1=1.1 to 4.0;D2=1.5 to
5.0; and(D2/D1)=1.05 to 4.55,wherein a hot-water shrinkability
(SM1) in a longitudinal direction and a hot-water shrinkability
(ST1) in a transverse direction of the first heat shrinkable
multilayer film and a hot-water shrinkability (SM2) in a
longitudinal direction and a hot-water shrinkability (ST2) in a
transverse direction of the second heat shrinkable multilayer film
satisfy the following conditions:SM1=5 to 40%;ST1=5 to
40%;SM2=2 to 25%;ST22 to 25%;(SM1/SM2)=1.2 to 12;
and(ST1/ST2)=1.2 to 12,(where the hot-water shrinkability is a
shrinkability (%) after immersing the heat shrinkable multilayer film
before drawing in hot water of a temperature of 90.degree. C. for 10
seconds); andsealing and further heat-shrinking the top film and the
bottom film.

Description:

TECHNICAL FIELD

[0001]The present invention relates to a deep drawing packaging container
formed by separately deep drawing a top film and a bottom film each made
of a heat shrinkable multilayer film, to a deep drawing packaged product
using the deep drawing packaging container and to methods for
manufacturing the deep drawing packaging container and the deep drawing
packaged product.

BACKGROUND OF THE INVENTION

[0002]Conventionally, as a method for packaging food such as processed
meat products, seafood paste products, meats, fishes, cheeses, there are
generally used a method for filling and packaging the contents into a bag
or a pouch bag made of an oriented/shrinkable or a
non-oriented/non-shrinkable multilayer film, and a method for filling and
packaging the contents into a bag made of a multilayer film just after
the bag is formed by a vertical (longitudinal) pillow/transverse
(horizontal) pillow type packaging machine. However, in a packaging
method using such bags, a method is used in which contents are filled in
a bag followed by evacuation at a reduced pressure or vacuum in a vacuum
chamber, and thereafter an opening portion is sealed to provide a
packaged product, so that, in a series of operations in such bag-type
vacuum packaging, increase in a filling rate has limitations.
Accordingly, a method that enables an increase in filling rate has been
demanded from economical and other point of view.

[0003]On the other hand, as a method easily increasing a filling rate
compared with the bag-type vacuum packaging method, there is a so-called
deep drawing packaging method utilizing vacuum packaging. Generally,
non-oriented/non-shrinkable multilayer films are conventionally used for
the deep drawing packaging method. Particularly, in the case where
irregular shapes of content such as meat, a ham, a roast pork and a bacon
are filled and packaged, there are drawbacks that the packaged product is
easily wrinkled, and that the films lack in a fitting property for the
contents, so that liquid of contents easily stays. Moreover, there is
also a drawback that keeping quality of contents becomes poor. In
addition, in deep drawing packaging using conventional
non-oriented/non-shrinkable multilayer films, a so-called flange portion
which is formed by closely attaching a top film with a bottom film not
contacting to contents is excessively large, so that there is a problem
that it is extremely difficult to obtain a packaging form similar to the
bag-type vacuum packaging.

[0004]In order to solve these problems, International Application
Japanese-Phase Publication No. 2003-535733 (Document 1) discloses a
stretch-oriented multilayer film including at least three layers of: a
surface layer (a) made of a thermoplastic resin; an intermediate layer
(b) made of a polyamide-based resin; and a surface layer (c) made of a
sealable resin. The multilayer film exhibits an impact energy of 1.5
Joule or more at a conversion thickness of 50 μm at a temperature of
-10° C. In the specification, there is described a deep drawing
package using such a stretch-oriented multilayer film.

[0005]However, in a deep drawing package, generally, a bottom film having
multiple concave portions is formed by deep drawing, and then contents
are filled into the concave portions. Then, a non-molded top film is
continuously covered onto the concave portions. After the container is
evacuated at a reduced pressure or vacuum in a vacuum chamber, deep
drawing packaged products are continuously obtained by heat-sealing a
peripheral part of an upper face of the bottom film with the top film.
Accordingly, even in the deep drawing packaged product described in
Document 1 and obtained by using a heat shrinkable film, a seal position
of the bottom film and the top film is eccentrically located in the
bottom film side. As a result, it is still difficult to obtain a
packaging form similar to the bag-type vacuum packaging.

DISCLOSURE OF THE INVENTION

[0006]The present invention has been made in consideration of the above
problems of the prior art, and it is an object of the present invention
to provide a deep drawing packaging container and a deep drawing packaged
product which are sufficiently prevented from generation of winkles in
the packaged product even when irregular shapes of contents such as meat
is filled and packaged; and which is possible to provide a packaging form
similar to the bag-type vacuum packaging by providing a small flange
portion because of tight fitness to contents even when a margin ratio of
the packaged product is large, and by locating the seal position of the
bottom film and the top film at a near-central part of the contents in a
thickness direction. Another object of the present invention is to
provide methods for manufacturing such a container and such a packaged
product.

[0007]As a result of diligent studies with the aim of accomplishing the
aforementioned objects, the present inventors come to achieve the present
invention by disclosing the following facts. The above-described object
can be achieved by setting a drawing ratio of the bottom film is set in
predetermined range which is lager than a drawing ratio of the top film
as well as by setting a hot-water shrinkability of the top film in a
predetermined range which is larger than a hot-water shrinkability of the
bottom film.

[0008]A deep drawing packaging container of the present invention
comprises: a top film made of a first heat shrinkable multilayer film;
and a bottom film made of a second heat shrinkable multilayer film, the
deep drawing packaging container being formed by deep drawing, so that a
drawing ratio (D1) of the top film and a drawing ratio (D2) of
the bottom film satisfy the following conditions:

D1=1.1 to 4.0;

D2=1.5 to 5.0; and

(D2/D1)=1.05 to 4.55,

wherein a hot-water shrinkability (SM1) in a longitudinal direction
and a hot-water shrinkability (ST1) in a transverse direction of the
first heat shrinkable multilayer film and a hot-water shrinkability
(SM2) in a longitudinal direction and a hot-water shrinkability
(ST2) in a transverse direction of the second heat shrinkable
multilayer film satisfy the following conditions:

SM1=5 to 40%;

ST1=5 to 40%;

SM2=2 to 25%;

ST2=2 to 25%;

(SM1/SM2)=1.2 to 12; and

(ST1/ST2)=1.2 to 12,

(where the hot-water shrinkability is a shrinkability (%) after immersing
the heat shrinkable multilayer film before drawing in hot water of a
temperature of 90° C. for 10 seconds).

[0009]In addition, a deep drawing packaged product of the present
invention comprises: a packaging container obtained by sealing and
further heat-shrinking the top film and the bottom film of the deep
drawing packaging container of the present invention; and contents placed
inside the packaging container.

[0010]In such a deep drawing package container and a deep drawing packaged
product of the present invention, each of the first heat shrinkable
multilayer film and the second heat shrinkable multilayer film preferably
comprises at least an outer layer made of a first thermoplastic resin, an
intermediate layer made of a polyamide-based resin and an inner layer
made of a sealant resin.

[0011]Moreover, a total thickness (T1) of the first heat shrinkable
multilayer film before drawing and a total thickness (T2) of the
second heat shrinkable multilayer film before drawing more preferably
satisfy the following conditions:

T1=20 to 120 μm;

T2=45 to 200 μm; and

(T2/T1)=1.1 to 10.

[0012]A method for manufacturing a deep drawing packaging container of the
present invention is a method for manufacturing a deep drawing packaging
container comprising a top film made of a first heat shrinkable
multilayer film and a bottom film made of a second heat shrinkable
multilayer film, the method comprising the steps of:

[0013]preparing the first heat shrinkable multilayer film and the second
heat shrinkable multilayer film in which a hot-water shrinkability
(SM1) in a longitudinal direction and a hot-water shrinkability
(ST1) in a transverse direction of the first heat shrinkable
multilayer film and a hot-water shrinkability (SM2) in a
longitudinal direction and a hot-water shrinkability (ST2) in a
transverse direction of the second heat shrinkable multilayer film
satisfy the following conditions:

SM1=5 to 40%;

ST1=5 to 40%;

SM2=2 to 25%;

ST2=2 to 25%;

(SM1/SM2)=1.2 to 12; and

(ST1/ST2)=1.2 to 12,

(where the hot-water shrinkability is a shrinkability (%) after immersing
the heat shrinkable multilayer film before drawing in hot water of a
temperature of 90° C. for 10 seconds); and

[0014]performing deep drawing so that a drawing ratio (D1) of the top
film and a drawing ratio (D2) of the bottom film satisfy the
following conditions:

D1=1.1 to 4.0;

D2=1.5 to 5.0; and

(D2/D1)=1.05 to 4.55.

[0015]Moreover, the method for manufacturing the deep drawing packaged
product of the present invention comprises the steps of:

[0016]placing contents in a space between the top film and the bottom film
of the deep drawing packaging container of the present invention, and

[0017]sealing and further heat-shrinking the top film and the bottom film.

[0018]In such methods of the present invention for manufacturing the deep
drawing packaging container and the deep drawing packaged product, each
of the first heat shrinkable multilayer film and the second heat
shrinkable multilayer film preferably comprises at least an outer layer
made of a first thermoplastic resin, an intermediate layer made of a
polyamide-based resin and an inner layer made of a sealant resin, and a
total thickness (T1) of the first heat shrinkable multilayer film
before drawing and a total thickness (T2) of the second heat
shrinkable multilayer film before drawing more preferably satisfy the
following conditions:

T1=20 to 120 μm;

T2=45 to 200 μm; and

(T2/T1)=1.1 to 10.

[0019]According to the present invention, it is possible to provide a deep
drawing packaging container and a deep drawing packaged product which
sufficiently prevents generation of winkles in the packaged product even
when irregular shapes of contents such as meat is filled and packaged;
provides small flange portion because of tight fitness to contents even a
margin ratio of the container being large; and is possible to be a
packaging form similar to the bag-type vacuum packaging by locating the
seal position of the bottom film and the top film in near-central part in
a thickness direction, and a method for manufacturing the same.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020]The following will specifically explain the present invention with
reference to preferred embodiments. First, an explanation will be given
of a deep drawing packaging container of the present invention and a
method for manufacturing the same. The deep drawing packaging container
of the present invention includes a top film made of a first heat
shrinkable multilayer film and a bottom film made of a second heat
shrinkable multilayer film.

[0021]Although the specific composition of such a heat shrinkable
multilayer film is not particularly limited, each of the first heat
shrinkable multilayer film and the second heat shrinkable multilayer film
preferably includes at least an outer layer made of a first thermoplastic
resin, an intermediate layer made of a polyamide-based resin and an inner
layer made of a sealant resin.

[0023]Moreover, the polyamide-based resin forming the intermediate layer
can include, for example, aliphatic polyamide polymers such as nylon 6,
nylon 66, nylon 11, nylon 12, nylon 69, nylon 610 and nylon 612, and
aliphatic polyamide copolymers such as nylon 6/66, nylon 6/69, nylon
6/610, nylon 66/610 and nylon 6/12. Of these polyamides, nylon 6/66 and
nylon 6/12 are preferable from a viewpoint of forming processability.
Moreover, for such polyamide-based resins, blends of these aliphatic
polyamide (co)polymers as main components with aromatic polyamides may be
used. Such aromatic polyamides mean that at least one of a diamine and a
dicarboxylic acid includes an aromatic unit. Examples of these aromatic
polyamides include nylon 66/610/MXD6 (polymetaxylylene adipamide), nylon
66/69/6I, nylon 6/6I, nylon 66/6I and nylon 6I/6T ("nylon 6I" indicating
polyhexamethylene isophthalamide and "nylon 6T" indicating
polyhexamethylene terephthalamide). As for these polyamide-based resins,
one species thereof may be singly used or a combination of two or more
species may be used, and polyamides having a melting point of 160 to
210° C. are more preferable. Moreover, these polyamide-based
resins may contain olefin-based resins modified with an acid such as
maleic acid or with an anhydride thereof, ethylene-acrylic acid
copolymer, ethylene-methacrylic acid copolymer, ionomer resin, and
saponified ethylene-vinyl acetate copolymer up to approximately 30% by
mass.

[0025]Heat shrinkable multilayer films suitable for the present invention
includes the above-described outer layer made of the first thermoplastic
resin, the intermediate layer made of a polyamide-based resin, and the
inner layer made of the sealant resin. However, intermediate layers other
than the intermediate layer made of a polyamide-based resin can be
included for the purpose of improving functionality or processability of
the multilayer films or other purposes, if necessary. Examples of such
other intermediate layers include, for example, the following gas-barrier
intermediate layer and the following adhesive resin layer.

[0026]Specifically, as gas-barrier resins forming a gas-barrier
intermediate layer and particularly used for an oxygen-gas-barrier layer,
a known saponified ethylene-vinyl acetate copolymer (EVOH); aromatic
polyamides having aromatic diamine such as polymetaxylylene adipamide
(nylon MXD6); amorphous aromatic polyamides having aromatic carboxylic
acid such as polyhexamethylene isophthalamide/terephthalamide (nylon
6I/6T) which is the copolymer of isophthalic acid, terephthalic acid and
hexamethylene diamine; and the like can be exemplified.

[0027]Moreover, when adhesion force between each layer is not sufficient,
an adhesive resin layer can be provided as an intermediate layer, if
necessary. As preferable adhesive resins, EVA, EEA, EAA, acid-modified
polyolefin (for example, acid-modified VLDPE, acid-modified LLDPE and
acid-modified LDPE), acid-modified EVA and the like can be used. Of these
adhesive resins, olefin-based resins which are modified with an acid such
as maleic acid, an anhydride thereof, or the like are preferably used.

[0029]The deep drawing packaging container of the present invention
includes the above-mentioned top film made of the first heat shrinkable
multilayer film and the above-mentioned bottom film made of the second
heat shrinkable multilayer film. The top film and the bottom film can be
obtained by deep drawing the heat shrinkable multilayer films in the
following drawing ratios.

[0030]The top film according to the present invention is obtained by deep
drawing the first heat shrinkable multilayer film in a drawing ratio
(D1) of 1.1 to 4.0. When a thickness of contents is thin, a small
drawing ratio may be acceptable. However, when the drawing ratio is less
than 1.1, wrinkles may occur in a packaged product because of
insufficient heat shrinkage, particularly in the case of a low value of
the heat shrinkability of the film. Meanwhile, when the drawing ratio of
the top film exceeds 4.0, the film may not be deep drawn because the film
is torn at deep drawing.

[0031]Moreover, the bottom film according to the present invention is
obtained by deep drawing the second heat shrinkable multilayer film in a
drawing ratio (D2) of 1.5 to 5.0. When the drawing ratio of the
bottom film is less than 1.5, wrinkles may occur in a packaged product
because of insufficient heat shrinkage, particularly in the case of a low
value of the heat shrinkability of the film. Meanwhile, although a
drawing ratio of 4.0 or more is required in the case of big- and
thick-shaped contents, when the drawing ratio of the bottom film exceeds
5.0, the film may not be deep drawn because the film is torn at deep
drawing.

[0032]Furthermore, for the deep drawing packaging container of the present
invention, a ratio (D2/D1) of a drawing ratio (D2) of the
bottom film to a drawing ratio (D1) of the top film needs to be in a
range of 1.05 to 4.55. When this ratio is less than 1.05, the deep
drawing packaged product becomes unstable during filling contents when
big-shaped contents are packaged, as well as movement of an upper chamber
of a packaging machine becomes bigger, so that its structure becomes
large. From a viewpoint of lifetime of the machine, smaller movement is
desirable. Meanwhile, when this ratio exceeds 4.55, the object of the
present invention will not be achieved, because a position of a seal line
is eccentrically located in the top film side.

[0033]Drawing ratios according to the present invention is determined as
follows.

<Drawing Ratio>

[0034]A surface area before deep drawing and a surface area after deep
drawing are both determined from a shape of a drawing mold. Then the
drawing ratio is calculated from the following formula:

{Surface area after deep drawing [cm2]}/{Surface area before deep
drawing [cm2]}=Drawing ratio [-]

[0035]In the deep drawing packaging container of the present invention,
after the first heat shrinkable multilayer film (before drawing) used for
the top film is immersed in hot-water at a temperature of 90° C.
for 10 seconds, a hot-water shrinkability (SM1) in a longitudinal
direction and a hot-water shrinkability (ST1) in a transverse
direction both need to be 5 to 40%, more preferably 10 to 35%, and
particularly preferably 5 to 30%. When the hot-water shrinkability
(SM1) in a longitudinal direction or the hot-water shrinkability
(ST1) in a transverse direction is less than 5%, wrinkle formation
in the obtained packaged product can not be prevented. Meanwhile, when
the hot-water shrinkability (SM1) in a longitudinal direction or the
hot-water shrinkability (ST1) in a transverse direction exceeds 40%,
deep drawing defects of causing clip unfastening because of too much
shrinkage during deep drawing, causing seal defects, lowering actual
drawing ratio of the film at deep drawing or the like are generated.

[0036]Moreover, after the second heat shrinkable multilayer film (before
drawing) used for the bottom film is immersed in hot-water at a
temperature of 90° C. for 10 seconds, a hot-water shrinkability
(SM2) in a longitudinal direction and a hot-water shrinkability
(ST2) in a transverse direction both needs to be 2 to 25%, and
particularly preferably 3 to 25%. When the hot-water shrinkability
(SM2) or the hot-water shrinkability (ST1) in a transverse
direction is less than 2%, wrinkle formation in the obtained packaged
product can not be prevented. Meanwhile, when the hot-water shrinkability
(SM2) or the hot-water shrinkability in a transverse direction
(ST1) exceeds 25%, deep drawing defects are generated.

[0037]Furthermore, in the deep drawing packaging container of the present
invention, a ratio (SM1/SM2) of the hot-water shrinkability
(SM1) of the top film to the hot-water shrinkability (SM2) of
the bottom film and a ratio (ST1/ST2) of the hot-water
shrinkability (ST1) of the top film to the hot-water shrinkability
(ST2) of the bottom film needs to be in a range of 1.2 to 12. When
this ratio is less than 1.2, wrinkle formation in the obtained packaged
product can not be prevented. Meanwhile, when this ratio exceeds 12, it
is difficult to obtain a packaging form similar to the bag-type vacuum
packaging because a seal poison of the top film and the bottom film is
eccentrically located in the top film side because of too much shrinkage
of the top film.

[0038]Note that, the hot-water shrinkability according to the present
invention is determined as follows.

<Hot-Water Shrinkability>

[0039]According to the method described in ASTM D2732-83, a hot-water
shrinkability is determined as follows. That is, a film sample is marked
at a distance of 10 cm in a mechanical direction (longitudinal direction)
and in a direction (transverse direction) perpendicular to the mechanical
direction of the film. The film sample is immersed in hot water with the
temperature thereof adjusted to 90° C., for 10 seconds, and
thereafter taken out and cooled with water at a room temperature
immediately. After that, the marked distance is measured, and a hot-water
shrinkability is calculated based on the following formula:

Then, each sample is tested five times, and an average value obtained for
each of the longitudinal direction (MD) and transverse direction (TD) is
expressed as a hot water shrinkability of the sample. That is, for the
hot water shrinkability according to the present invention, both the hot
water shrinkability in a mechanical direction (longitudinal direction)
and the hot water shrinkability in a direction (transverse direction)
perpendicular to the mechanical direction needs to be in a range
satisfying the conditions described in claims.

[0040]Moreover, a method for obtaining a heat shrinkable multilayer film
having such a hot water shrinkability is not particularly limited. For
example, a heat shrinkable multilayer film satisfying the above-described
conditions can be obtained by setting a relaxation ratio at forming of
the heat shrinkable multilayer film used for the top film to 5 to 25% and
a relaxation ratio at forming of the heat shrinkable multilayer film used
for the bottom film to 10 to 30%.

[0041]In a deep drawing packaging container of the present invention, a
total thickness (T1) of a first heat shrinkable multilayer film used
for the top film before drawing is preferably 20 to 120 μm, more
preferably 30 to 100 μm, and particularly preferably 40 to 90 μm.
When the total thickness (T1) of a film used for a top film is less
than 20 μm, there is a tendency that thickness control at film forming
of the heat shrinkable multilayer film is difficult, and, as for film
properties, oxygen gas permeability becomes high as well as strength
becomes low. Meanwhile, when the total thickness (T1) exceeds 120
μm, there is a tendency that strength of the top film becomes
excessively high and the cost becomes high.

[0042]Moreover, a total thickness (T2) of the second heat shrinkable
multilayer film used for the bottom film before drawing is preferably 45
to 200 μm, more preferably 60 to 150 μm, and particularly
preferably 70 to 140 μm. When the total thickness (T2) of the
film used for the bottom film is less than 50 μm, there is a tendency
that deep drawing formability becomes poor, and, as for film properties,
oxygen gas permeability becomes high as well as strength becomes low.
Meanwhile, when the total thickness (T2) exceeds 200 μm, there is
a tendency that the strength of the top film becomes excessively high and
the cost becomes high.

[0043]Furthermore, in the deep drawing packaging container of the present
invention, a ratio (T2/T1) of the total thickness (T2) of
the second heat shrinkable multilayer film used for the bottom film
before drawing to the total thickness (T1) of the first heat
shrinkable multilayer film used for the top film before drawing is
preferably in a range of 1.1 to 10. When this ratio is less than 1.1,
there is a tendency that a position of a seal line is eccentrically
located in the top film side in the case of large shrinkability and a
small drawing ratio of the top film. Meanwhile, when this ratio exceeds
10, a thickness of the top film to a thickness of the bottom film becomes
too thin.

[0044]A thickness of the multilayer film according to the present
invention is obtained by measuring thickness of each layer and total
thickness in the cross-section of the multilayer film with an optical
microscope manufactured by Olympus Corporation.

[0045]Although oxygen gas transmission rate (O2TR) of the heat
shrinkable multilayer film used in the present invention is not
particularly limited, for example, in the case of packaging raw meat,
each oxygen gas transmission rate of the heat shrinkable multilayer film
used for the top film and the bottom film is preferably 1 to 100
cm3/m2dayatm, more preferably 1 to 80 cm3/m2dayatm,
and particularly preferably 1 to 60 cm3/m2dayatm under
conditions of a temperature of 23° C. and of 80% RH. When the
oxygen gas transmission rate exceeds 100 cm3/m2dayatm, there is
a tendency that storage stability is lowered by oxidation deterioration
and storage for 40 days can not be achieved under a condition of
5° C. or less when raw meat is packaged.

[0046]Moreover, when cheese is packaged, each oxygen gas transmission rate
of the heat shrinkable multilayer film used for the top film and the
bottom film is preferably 50 to 400 cm3/m2dayatm under
conditions of a temperature of 23° C. and of 80% RH. When the
oxygen gas transmission rate is less than 50 cm3/m2dayatm,
there is a tendency that appearance of a packaged product tends to
deteriorate by expansion of the packaged product because of gas generated
when the cheese is fermented. Meanwhile, when the oxygen gas transmission
rate exceeds 400 cm3/m2dayatm, there is a tendency that a
storage period of cheese becomes short.

[0047]An oxygen gas transmission rate according to the present invention
is determined as follows.

<Oxygen Gas Transmission Rate>

[0048]According to the method described in ASTM D3985-81, an oxygen gas
transmission rate under conditions of a temperature of 23° C. and
of 80% RH is measured in film state of each heat shrinkable multilayer
film used for a top film and a bottom film, using MOCON PERMATRAN
manufactured by MODERN CONTROL Inc. The measuring unit is
"cm3/m2dayatm".

[0049]Although a water vapor transmission rate (WVTR) of the heat
shrinkable multilayer film used in the present invention is also not
particularly limited. However, each water vapor transmission rate of the
heat shrinkable multilayer film used for the top film and the bottom film
is preferably 30 g/m2day or less, more preferably 25 g/m2day or
less, and particularly preferably 20 g/m2day or less. When the water
vapor transmission rate exceeds 30 g/m2day, there is a tendency that
weight decrease of the contents becomes too much.

[0050]A water vapor transmission rate according to the present invention
is determined as follows.

<Water Vapor Transmission Rate>

[0051]According to the method described in ASTM F1249-90, a water vapor
transmission rate under conditions of a temperature of 40° C. and
of 90% RH is measured in film state of each heat shrinkable multilayer
film used for a top film and a bottom film, using MOCON PERMATRAN-W
manufactured by MODERN CONTROL Inc. The measuring unit is "g/m2day".

[0052]Moreover, puncture strength of the heat shrinkable multilayer film
used in the present invention is preferably 10N or more. When the
puncture strength is less than 10N, there is a tendency that the film
tends to tear in the case of packaging bony chops or the like.

[0053]Puncture strength according to the present invention is determined
as follows.

<Puncture Strength>

[0054]Under atmosphere of a temperature of 23° C. and of 50% RH, a
needle for puncture is stuck into a sample (multilayer film) from an
outer layer at a speed of 50 mm/min using a tensile tester (TENSILON
RTM-100, manufactured by ORIENTEC Co., LTD.) equipped with the needle for
puncture having a hemispherical tip with a curvature radius of 0.5 mm,
and a maximum value (N) up to break is defined as puncture strength. Each
of the heat shrinkable multilayer films used for the top film and the
bottom film in a film state is measured.

[0055]In the present invention, a deep drawing packaging container of the
present invention is obtained by preparing a first heat shrinkable
multilayer film and a second heat shrinkable multilayer film satisfying
the above-described conditions, and deep drawing such that a drawing
ratio (D1) of a top film and a drawing ratio (D2) of a bottom
film satisfies the above-described conditions.

[0056]Moreover, a deep drawing packaged product is obtained by placing
contents, which is to be filled, in a space between the top film and the
bottom film of the deep drawing packaging container of the present
invention, and sealing and further heat shrinking the top film and the
bottom film.

[0057]In the present invention, any one of methods of a series of means in
processes for obtaining a deep drawing packaged product such as a method
for forming a concave portion in a top film and a bottom film by deep
drawing, a method for placing contents in a space between the top film
and the bottom film, a method for placing the top film and the bottom
film so as to face each other, a method for sealing (preferably heat
sealing) the top film and the bottom film, a method for heat shrinking
the sealed top and bottom films, and a method for cutting the top film
and the bottom film at predetermined position is not particularly
limited, and known methods in relation to deep drawing can be optionally
employed. Moreover, before sealing the top film and the bottom film,
reduced pressure (vacuum) evacuation of a space between the top film and
the bottom film in a vacuum chamber is preferably performed. However, gas
exchange in the space with predetermined gas can be possible.

[0058]In a conventional non-oriented/non-shrinkable multilayer film, since
a drawing part of the film does not shrink, contents must be filled such
that a ratio of volume of the contents to a volume of the drawing mold is
90 to 95% (filling ratio=90 to 95%) in order to obtain a packaged product
without wrinkles. Even so, wrinkles may occur in a part of the packaged
product or seal breakage may occur when filling ratio becomes high. In
contrast, according to the present invention, a packaged product having
excellent appearance and no-wrinkles is obtained in a wide range of
filling ratio of 50 to 95%.

[0059]That is, in the present invention, the filling ratio is preferably
50 to 95%, more preferably 60 to 95%, and particularly preferably 60 to
90%. When the filling ratio is less than 50%, there is a tendency that
wrinkles are easily generated in the packaged product. Meanwhile, when
the filling ratio exceeds 95%, there is a tendency that filling is
difficult when contents are filled in a drawing part, and seal breakage
easily occurs.

[0060]A filling ratio according to the present invention is determined as
follows.

<Filling Ratio>

[0061]For a volume of contents, the contents are immersed into a water
bath fully filled with water at 23° C., and a volume of the
contents is determined by measuring a volume of spilled water. The
filling ratio is calculated according to the following formula:

{Volume of contents [cm3]}/{Total volume of concave portion (mold) of
top film and concave portion (mold) of bottom film
[cm3]}×100=Filling ratio [%].

[0062]In the present invention, since both the top film and the bottom
film are deep drawn as described above, the sealing position of the top
film and the bottom film can be adjusted in wide range by adjusting a
drawing ratio of the top film and the bottom film, a heat shrinkability
of the top film and the bottom film, or the like. As a result, the
sealing position can be adjusted so as to locate the sealing position
near the center of the thickness direction of the contents. Therefore,
according to the present invention, a deep drawing packaged product whose
packaging form is similar to a conventional bag-type vacuum packaging can
be obtained. Accordingly, a filling rate is easily improved compared with
a conventional bag-type vacuum packaging, and consequently laborsaving
and cost reduction become possible by obtaining the packaging form being
similar to a bag-type vacuum packaging by deep drawing.

[0063]Moreover, according to the present invention, generation of wrinkles
can sufficiently be prevented, and at the same time, a flange portion
becomes small. Accordingly, when the deep drawing packaged product of the
present invention is applied, for example, to a whole-chicken bag-type
packaging, and tightly-fitted to the contents with flexibility, the
whole-chicken looks as if the whole-chicken were not packaged, and this
provides fresh appearance compared with a conventional package.
Furthermore, when the deep drawing packaged product of the present
invention is applied to a package of a box-shaped block of ham or a
box-shaped block of cheese, since the same form is viewed from either a
top film side or bottom film side by locating a sealing position near the
center of the thickness direction of the contents, there is also an
advantage that sales persons can easily display the commercial products.

EXAMPLES

[0064]The following will specifically explain the present invention based
on Examples and Comparative Examples, but the present invention is not
limited to the following Examples. Additionally, the following Table 1
collectively shows resins used in Examples and Comparative Examples are
shown together with their abbreviations. Moreover, Tables 2 to 5
collectively shows compositions, physical properties and measured values
of heat shrinkable multilayer films used in Examples 1 to 9 and
Comparative Examples 1 to 4 and 7.

Example 1

[0065]In order to achieve the layer structures of PET (3)/M-PE-1 (2)/Ny-1
(11)/EVOH (4)/M-PE-1 (2)/VLDPE (20) where the layers were formed from the
outer side to the inner side sequentially with a thickness ratio of
layers indicated in the parentheses, the respective resins were extruded
by plural extruders. Then, melted resins were introduced to an annular
die, and the introduced resins were adhered to obtain the aforementioned
layer structure.

[0066]Thus, co-extrusion process was performed. A melted tubular body
extruded from an outlet of the die is cooled with water at 15 to
25° C. using cooling showering to obtain a parison. The obtained
parison was passed through a hot water bath at 89° C. to
thereafter obtain a tubular film. The tubular film was biaxially
stretched in a longitudinal direction (MD) with a stretching ratio of 2.8
times and in a transverse direction (TD) with an stretching ratio of 3.1
times simultaneously by an inflation method while being cooled by airing
at 15 to 20° C. Then, the obtained biaxially oriented film was
guided into a heat treatment tower having a tube length of 2 m to obtain
a tubular film. The tubular film was heated at 68° C. with steam
blown from a blowout opening and the heated film is subjected to heat
treatment for 2 seconds while being relaxed by 10% in the longitudinal
direction and by 10% in the transverse direction to obtain a top film (A)
of a biaxially oriented film (a stretch-oriented multilayer film).

[0067]Moreover, a bottom film (a) of a biaxially oriented film (a
stretch-oriented multilayer film) was obtained in the same way as the top
film (A) except that layer structure, film thickness and film forming
(stretching-relaxation) conditions were changed as described in Table 2.

[0068]A hot-water shrinkability, puncture strength, an oxygen gas
transmission rate (O2TR), and a water vapor transmission rate were
measured for each of the obtained top and bottom films. Furthermore,
evaluation of a packaging test for a box-shaped block of ham was
conducted as a practical test. Table 2 shows the obtained results.

<Packaging Test for a Box-Shaped Block of Ham>

[0069]The bottom film was deep drawn by a mold for the bottom film
(longitudinal direction: 100 mm, transverse direction: 110 mm, depth: 40
mm) under conditions of a forming temperature of 85° C., a forming
time of 2.0 seconds, a degree of vacuum of 10 mbar and a drawing ratio of
2.5 using a deep drawing machine R550 manufactured by Multivac Sepp
Haggenmuller GmbH & Co. The box-shaped block of ham (longitudinal
direction: 90 mm, transverse direction: 100 mm, height: 60 mm, weight:
approximately 600 g) was placed as the content in the formed concave
portion. Moreover, the top film was deep drawn by a mold for the top film
(longitudinal direction: 100 mm, transverse direction: 110 mm, depth: 30
mm) under conditions of a forming temperature of 85° C., a forming
time of 2.0 seconds, a degree of vacuum of 10 mbar and a drawing ratio of
2.1. The top film was oppositely placed on the bottom film filled with
the content, and the top film and the bottom film were heat sealed under
conditions of 130° C. for 2 seconds in a vacuum chamber while the
inside was being evacuated. Then, after the top film and the bottom film
were cut so as to form a flange portion with a length at the cutting of
30 mm, the obtained product was immersed into a shrinker (hot water bath)
for heat shrinking under conditions of 85° C. for 1 second to
obtain a deep drawing packaged product.

[0070]Then, the appearance of the obtained deep drawing packaged product
was evaluated in terms of the following three evaluation categories based
on the following judging standards. Table 2 shows the obtained results.

[0071](1) Length of Flange Portion in Packaged Product

A: A length of flange portion except opening part of the packaged product
to the length of flange portion at cutting (original dimension of cut
length) is less than 70%. The result is good.C: A length of flange
portion to the length of flange portion at cutting (original dimension of
cut length) is 70% or more. The result is poor.

[0072](2) Wrinkles in Packaged Product Surface

A: No wrinkles exist on the surfaces except the side surface of the
packaged product, and the appearance of the packaged product is smooth.B:
1 to 5 wrinkle(s) are generated on the surfaces except the side surface
of the packaged product.C: More than 6 wrinkles are generated on the
surfaces except the side surface of the packaged product.

[0073](3) Sealing Position in Side Surface

A: A sealing position of the top film and the bottom film is located
within a range of ±35% from the center of the thickness direction of
the content having the height of 60 mm, and the packaging form is similar
to a bag-type vacuum packaging.C: A sealing position of the top film and
the bottom film is located out of a range of +35% from the center of the
thickness direction of the content having the height of 60 mm, and the
packaging form is not similar to a bag-type vacuum packaging.

Examples 2 to 9

[0074]A top film and a bottom film used in each Example were obtained in
the same way as Example 1 except that layer structure, film thickness and
film forming (stretching-relaxation) conditions were changed as described
in Tables 2 to 4. Each property was measured in the same way as Example 1
for the obtained top films and bottom films, and the practical test was
further conducted. Tables 2 to 4 show the obtained results.

Comparative Example 1

[0075]In order to achieve the layer structures of PE (17)/M-PE-1 (4)/Ny-1
(2)/EVOH (6)/Ny-1 (2)/M-PE-1 (4)/LLDPE (25) where the layers were formed
from the outer side to the inner side sequentially with a thickness ratio
of layers indicated in the parentheses, the respective resins were
extruded by plural extruders. Then, melted resins were introduced to a
T-die, and the introduced resins were adhered to obtain the
aforementioned layer structure. Thus, co-extrusion process was performed
to form a multilayer film. Then, the obtained multilayer film was
laminated with a biaxially oriented nylon film (shrinkable, O-Ny) to
obtain a top film (G). Meanwhile, the bottom film (a) obtained in Example
1 is used as a bottom film. Each property was measured in the same way as
Example 1 for the obtained top and bottom films, and the practical test
was further conducted. Table 4 shows the obtained results.

Comparative Example 2

[0076]A Top film and a bottom film used in this Comparative Example were
obtained in the same way as Example 1 except that layer structure, film
thickness and film forming (stretching-relaxation) conditions were
changed as described in Table 4. Each property was measured in the same
way as Example 1 for the obtained top and bottom films, and the practical
test was further conducted. Table 4 shows the obtained results.

[0077]As being obvious from the results shown in Tables 2 to 4, all
results of each physical property and packaging test for the box-shaped
block of ham were excellent for the deep drawing packaged products of the
present invention (Examples 1 to 9) using the deep drawing packaging
containers of the present invention. Meanwhile, as being obvious from the
results shown in table 4, for the deep drawing packaged product of
Comparative Example 1 which did not satisfy the conditions according to
the present invention, shrinkage of the flange portion was insufficient,
and furthermore, many wrinkles were generated in the surface of the
packaged product, so that the result was unsatisfactory. Moreover, for
the deep drawing packaged product of Comparative Example 2 which did not
satisfy the conditions according to the present invention, the sealing
position of the top film and the bottom film is eccentrically located in
the top film side, so that the result was unsatisfactory.

Comparative Example 3

[0078]A top film and a bottom film used in this Comparative Example was
obtained in the same way as Example 1 except that layer structure, film
thickness and film forming (stretching-relaxation) conditions were
changed as described in Table 5. A deep drawing packaged product made of
the obtained the top film and the bottom film was tried to be obtained in
the same way as Example 1. However, the deep drawing packaged product
could not be obtained because of generation of film rupture (tearing) at
drawing of the bottom film.

Comparative Example 4

[0079]A top film and a bottom film used in this Comparative Example was
obtained in the same way as Example 1 except that layer structure, film
thickness and film forming (stretching-relaxation) conditions were
changed as described in Table 5. That is, the bottom film was used
without heat relaxation treatment. A deep drawing packaged product made
of the obtained top and bottom films was tried to be obtain in the same
as Example 1. However, the deep drawing packaged product could not be
obtained because clamp unfastening and drawing fault (a phenomenon of
being not able to draw in a close shape to the mold shape) occurred due
to the large shrinkability (stress) at drawing of the bottom film.

Example 10

[0080]A bottom film (c) obtained in Example 3 was deep drawn by a mold for
the bottom film (longitudinal direction: 310 mm, transverse direction:
160 mm, depth: 100 mm) under conditions of a forming temperature of
85° C., a forming time of 2.0 seconds, a degree of vacuum of 10
mbar and a drawing ratio of 2.8 using a deep drawing machine R550
manufactured by Multivac Sepp Haggenmuller GmbH & Co. Raw meat
(longitudinal direction: approximately 300 mm, transverse direction:
approximately 150 mm, height: approximately 120 mm, weight: approximately
5.0 kg) was placed as the content in the formed concave portion.
Moreover, a top film (A) obtained in Example 3 was deep drawn by a mold
for the top film (longitudinal direction: 310 mm, transverse direction:
160 mm, depth: 40 mm) under conditions of a forming temperature of
85° C., a forming time of 2.0 seconds, a degree of vacuum of 10
mbar and a drawing ratio of 1.6. The top film was oppositely placed on
the bottom film filled with the content, and the top film and the bottom
film were heat sealed under conditions of 130° C. for 2 seconds in
a vacuum chamber while the inside was being evacuated. Then, after the
top film and the bottom film were cut so as to form a flange portion with
a length at the cutting of 30 mm, the obtained product was immersed into
a shrinker (hot water bath) for heat shrinking under conditions of
85° C. for 1 second to obtain the deep drawing packaged product.

[0081]For the obtained deep drawing packaged product of the present
invention, there were no wrinkles and a length of the flange portion
after shrinkage is shorter than 20 mm. Moreover, it was recognized that
the sealing position of the top film and the bottom film was located
within a range of ±35% from the center of the thickness direction of
the content, and the packaging form was similar to a bag-type vacuum
packaging.

Example 11

[0082]A bottom film (c) obtained in Example 3 was deep drawn by a mold for
the bottom film (longitudinal direction: 250 mm, transverse direction:
200 mm, depth: 90 mm) under conditions of a forming temperature of
85° C., a forming time of 2.0 seconds, a degree of vacuum of 10
mbar and a drawing ratio of 2.4 using a deep drawing machine R550
manufactured by Multivac Sepp Haggenmuller GmbH & Co. A whole-chicken
(weight: approximately 1.0 kg) was placed as the content in the formed
concave portion. Moreover, a top film (A) obtained in Example 3 was deep
drawn by a mold for the top film (longitudinal direction: 250 mm,
transverse direction: 200 mm, depth: 40 mm) under conditions of a forming
temperature of 85° C., a forming time of 2.0 seconds, a degree of
vacuum of 10 mbar and a drawing ratio of 1.6. The top film was oppositely
placed on the bottom film filled with the content, and the top film and
the bottom film were heat sealed under conditions of 130° C. for 2
seconds in a vacuum chamber while the inside was being evacuated. Then,
after the top film and the bottom film were cut so as to form a flange
portion with a length at the cutting of 20 mm, the obtained product was
immersed into a shrinker (hot water bath) for heat shrinking under
conditions of 85° C. for 1 second to obtain the deep drawing
packaged product.

[0083]For the obtained deep drawing packaged product of the present
invention, there were no wrinkles and a length of the flange portion
after shrinkage was shorter than 14 mm. Moreover, it was recognized that
the sealing position of the top film and the bottom film was located
within a range of ±35% from the center of the thickness direction of
the content, and the packaging form was similar to a bag-type vacuum
packaging.

Example 12

[0084]A bottom film (d) obtained in Example 4 was deep drawn by a mold for
the bottom film (longitudinal direction: 130 mm, transverse direction:
340 mm, depth: 70 mm) under conditions of a forming temperature of
85° C., a forming time of 2.0 seconds, a degree of vacuum of 10
mbar and a drawing ratio of 1.79 using a deep drawing machine R550
manufactured by Multivac Sepp Haggenmuller GmbH & Co. A block of cheese
(longitudinal direction: approximately 120 mm, transverse direction:
approximately 330 mm, height: approximately 100 mm, weight: approximately
4 kg) was placed as the content in the formed concave portion. Moreover,
a top film (B) obtained in Example 4 was deep drawn by a mold for the top
film (longitudinal direction: 130 mm, transverse direction: 340 mm,
depth: 40 mm) under conditions of a forming temperature of 85° C.,
a forming time of 2.0 seconds, a degree of vacuum of 10 mbar and a
drawing ratio of 1.56. The top film was oppositely placed on the bottom
film filled with the content, and the top film and the bottom film were
heat sealed under conditions of 130° C. for 2 seconds in a vacuum
chamber while the inside was being evacuated. Then, after the top film
and the bottom film were cut so as to form a flange portion with a length
at the cutting of 30 mm, the obtained product was immersed into a
shrinker (hot water bath) for heat shrinking under conditions of
85° C. for 1 second to obtain the deep drawing packaged product.

[0085]For the obtained deep drawing packaged product of the present
invention, there were no wrinkles and a length of the flange portion
after shrinkage is shorter than 10 mm. Moreover, it was recognized that
the sealing position of the top film and the bottom film was located in
the top film side at 20% from the center of the thickness direction of
the content, and the packaging form was similar to a bag-type vacuum
packaging.

Comparative Example 5

[0086]A bottom film (a) obtained in Comparative Example 1 was deep drawn
by a mold for the bottom film (longitudinal direction: 320 mm, transverse
direction: 185 mm, depth: 50 mm) under conditions of a forming
temperature of 85° C., a forming time of 2.0 seconds, a degree of
vacuum of 10 mbar and a drawing ratio of 1.5 using a deep drawing machine
R550 manufactured by Multivac Sepp Haggenmuller GmbH & Co. Raw meat
(longitudinal direction: approximately 310 mm, transverse direction:
approximately 150 mm, height: approximately 80 mm, weight: approximately
4.0 kg) was placed as the content in the formed concave portion.
Moreover, a top film (G) obtained in Comparative Example 1 was deep drawn
by a mold for the top film (longitudinal direction: 320 mm, transverse
direction: 185 mm, depth: 40 mm) under conditions of a forming
temperature of 85° C., a forming time of 2.0 seconds, a degree of
vacuum of 10 mbar and a drawing ratio of 1.3. The top film was oppositely
placed on the bottom film filled with the content, and the top film and
the bottom film were heat sealed under conditions of 130° C. for 2
seconds in a vacuum chamber while the inside was being evacuated. Then,
after the top film and the bottom film were cut so as to form a flange
portion with a length at the cutting of 30 mm, the obtained product was
immersed into a shrinker (hot water bath) for heat shrinking under
conditions of 85° C. for 1 second to obtain the deep drawing
packaged product.

[0087]For the obtained deep drawing packaged product which did not satisfy
the conditions according to the present invention, it was recognized that
many wrinkles are generated in the surface because the flange portion did
not shrink and more than 25 cm of the flange portion was left, and
furthermore, shrinkage of the top film was insufficient.

Comparative Example 6

[0088]A bottom film (g) obtained in Comparative Example 2 was deep drawn
by a mold for the bottom film (longitudinal direction: 250 mm, transverse
direction: 200 mm, depth: 80 mm) under conditions of a forming
temperature of 85° C., a forming time of 2.0 seconds, a degree of
vacuum of 10 mbar and a drawing ratio of 2.5 using a deep drawing machine
R550 manufactured by Multivac Sepp Haggenmuller GmbH & Co. A
whole-chicken (weight: approximately 1.0 kg) was placed as the content in
the formed concave portion. Moreover, A top film (C) obtained in
Comparative Example 2 was deep drawn by a mold for the top film
(longitudinal direction: 250 mm, transverse direction: 200 mm, depth: 10
mm) under conditions of a forming temperature of 85° C., a forming
time of 2.0 seconds, a degree of vacuum of 10 mbar and a drawing ratio of
1.2. The top film was oppositely placed on the bottom film filled with
the content, and the top film and the bottom film were heat sealed under
conditions of 130° C. for 2 seconds in a vacuum chamber while the
inside was being evacuated. Then, after the top film and the bottom film
were cut so as to form a flange portion with a length at the cutting of
20 mm, the obtained product was immersed into a shrinker (hot water bath)
for heat shrinking under conditions of 85° C. for 1 second to try
to obtain the deep drawing packaged product. As a result, seal breakage
occurred because too much shrinkage of the top film occurred during heat
shrinkage.

Comparative Example 7

[0089]A top film and a bottom film used in this Comparative Example were
obtained in the same way as Example 1 except that layer structure, film
thickness and film forming (stretching-relaxation) conditions were
changed as described in Table 5.

[0090]Then, as a practical test, the bottom film was deep drawn by a mold
for the bottom film (circular form having a diameter of 98 mm, depth: 30
mm) under conditions of a forming temperature of 100° C., a
forming time of 2 seconds, and a drawing ratio of 2.2 using a deep
drawing machine "FV-603" manufactured by Omori Machinery Co., Ltd. Five
sheets of rubber plate (diameter: 95 mm, circular form, thickness: 5 mm,
weight: 60 g per sheet) were placed as the content in the formed concave
portion. Then, the top film was used without deep drawing. The top film
was placed on the bottom film filled with the content, and the top film
and the bottom film were heat sealed under conditions of 130° C.
for 2 seconds in a vacuum chamber while the inside was being evacuated.
Then, after the top film and the bottom film were cut so as to form a
flange portion with a length at the cutting of 30 mm, the obtained
product was immersed into a shrinker (hot water bath) for heat shrinking
under conditions of 85° C. for 1 second to obtain the deep drawing
packaged product.

[0091]For the obtained deep drawing packaged product which did not satisfy
the conditions according to the present invention, the sealing position
of the top film and the bottom film was eccentrically located in the top
film side, and the result was unsatisfactory.

INDUSTRIAL APPLICABILITY

[0092]As described above, according to the present invention, it is
possible to provide a deep drawing packaging container and a deep drawing
packaged product which are sufficiently prevented from generation of
winkles in the packaged product even when irregular shapes of contents
such as meat is filled and packaged; provides small flange portion
because of tight fitness to contents even a margin ratio of the container
being large; and which is possible to be a packaging form similar to the
bag-type vacuum packaging by locating the seal position of the bottom
film and the top film in near-central part in a thickness direction, and
methods for manufacturing the same.

[0093]Accordingly, the present invention is very useful as a technology in
relation with deep drawing package for which a filling rate is easily
improved compared with a conventional bag-type vacuum packaging, and
consequently laborsaving and cost reduction become possible.